Spacecraft and landing method

Abstract

A spacecraft ( 10 ) that includes a body ( 1 ); a rocket engine ( 2 ) installed in the body; an aerodynamic element ( 5 ) which is installed in the body and on which aerodynamic force acts; a measurement quantity acquiring system ( 7 ) configured to acquire at least one measurement quantity of the spacecraft; and a control device ( 8 ) configured to calculate an operation quantity to operate at least one of a gimbal angle of the rocket engine and an aerodynamic characteristic of the aerodynamic element. The control device ( 8 ) is configured to calculate the operation quantity according to the measurement quantity by a non-linear optimal control using a stable manifold method in the attitude change such that the attitude angle of the spacecraft ( 10 ) changes to the target attitude angle.

1 . A spacecraft configured to carry out an attitude change to a target attitude angle for a vertical landing after reentry into the atmosphere in a nose entry, and to land after the attitude change, comprising:
 a body;   a rocket engine installed on the body;   an aerodynamic element which is installed on the body and on which an aerodynamic force acts;   a measurement quantity acquiring system configured to acquire at least one measurement quantity of the spacecraft; and   a control device configured to calculate an operation quantity for an operation of at least one of a gimbal angle of the rocket engine and an aerodynamic characteristic of the aerodynamic element,   wherein the control device is configured to calculate the operation quantity according to the measurement quantity by a non-linear optimal control using a stable manifold method in the attitude change such that the attitude angle of the spacecraft is changed to the target attitude angle.   
     
     
         2 . The spacecraft according to  claim 1 , wherein the at least one measurement quantity contains an angle-of-attack of the spacecraft, and
 wherein the control device controls the attitude angle of the spacecraft in response to the angle-of-attack in the attitude change.   
     
     
         3 . The spacecraft according to  claim 1 , wherein the control device calculates the angle-of-attack of the spacecraft based on the at least one measurement quantity, and
 wherein the control device controls the attitude angle of the spacecraft in response to the calculated angle-of-attack in the attitude change.   
     
     
         4 . The spacecraft according to  claim 3 , wherein the at least one measurement quantity contains an acceleration of the spacecraft, and
 wherein the control device calculates the angle-of-attack of the spacecraft based on the acceleration.   
     
     
         5 . The spacecraft according to  claim 1 , wherein the control device controls the spacecraft to start the attitude change after the spacecraft reaches a setting region set previously above a landing point for the spacecraft to be landed, and to descend and land at the landing point, while controlling a position of the spacecraft in a horizontal plane, after the attitude angle of the spacecraft is controlled to the target attitude angle through the attitude change. 
     
     
         6 . A spacecraft configured to carry out an attitude change to a target attitude angle for a vertical landing after reentry into the atmosphere in a nose entry and to land after the attitude change, comprising:
 a body;   a rocket engine installed on the body;   an aerodynamic element which is installed on the body and on which an aerial force acts;   a measurement quantity acquiring system configured to acquire at least one measurement quantity of the spacecraft; and   a control device configured to calculate an operation quantity for an operation of at least one of a gimbal angle of the rocket engine and an aerodynamic characteristic of the aerodynamic element,   wherein the at least one measurement quantity contains an angle-of-attack of the spacecraft, and   wherein the control device is configured to calculate the operation quantity such that the attitude angle of the spacecraft changes to the target attitude angle according to the said angle-of-attack in the attitude change.   
     
     
         7 . A landing method of a spacecraft which comprises a body; a rocket engine installed on the body; and an aerodynamic element installed on the body for an aerial force to act,
 the landing method comprising:   (A) reentering a spacecraft into the atmosphere in a nose entry;   (B) carrying out an attitude change of the spacecraft such that an attitude angle of the spacecraft changes to a target attitude angle in which a vertical landing is carried out, after the (A) step; and   (C) carrying out the vertical landing of the spacecraft after the attitude change,   wherein the (B) step comprises:   acquiring at least one measurement quantity of the spacecraft; and   calculating an operation quantity to operate at least one of a gimbal angle of the rocket engine and an aerodynamic characteristic of the aerodynamic element according to the measurement quantity by a non-linear optimal control using a stable manifold method such that the attitude angle of the spacecraft changes to a target attitude angle.   
     
     
         8 . The landing method of the spacecraft according to  claim 7 , further comprising:
 (D) making the spacecraft fly while getting a lift force from the atmosphere such that the spacecraft reaches a setting region set previously near a landing point at which the spacecraft is to be landed,   wherein the attitude change is started after the spacecraft reaches the setting region.